.drop extent tags

The command runs in the context of a specific database. It drops specific extent tags from all or specific extents in the database and table.

Note

Data shards are called extents in Kusto, and all commands use "extent" or "extents" as a synonym. For more information on extents, see Extents (Data Shards) Overview.

There are two ways to specify which tags should be removed from which extents:

• Explicitly specify the tags that should be removed from all extents in the specified table.
• Provide a query whose results specify the extent IDs in the table, and for each extent - the tags that should be removed.

Syntax

.drop [async] extent tags from table TableName ('Tag1'[,'Tag2',...,'TagN'])

.drop [async] extent tags <| query

async (optional): Execute the command asynchronously.

• An Operation ID (Guid) is returned.
• The operation's status can be monitored. Use the .show operations command.
• Use the .show operation details command to retrieve the results of a successful execution.

Restrictions

All extents must be in the context database, and must belong to the same table.

Specify extents with a query

The extents and the tags to drop are specified using a Kusto query. It returns a recordset with a column called "ExtentId" and a column called "Tags".

Note

When using the Kusto .NET client library, the following methods will generate the required command:

• CslCommandGenerator.GenerateExtentTagsDropByRegexCommand(string tableName, string regex)
• CslCommandGenerator.GenerateExtentTagsDropBySubstringCommand(string tableName, string substring)

Requires Table admin permission for all involved source and destination tables.

Syntax for .drop extent tags in query

.drop extent tags <| ...query...

Return output

Output parameter	Type	Description
OriginalExtentId	string	A unique identifier (GUID) for the original extent whose tags have been modified. The extent is dropped as part of the operation.
ResultExtentId	string	A unique identifier (GUID) for the result extent that has modified tags. The extent is created and added as part of the operation. Upon failure - "Failed".
ResultExtentTags	string	The collection of tags that the result extent is tagged with, if any remain, or "null" in case the operation fails.
Details	string	Includes the failure details if the operation fails.

Examples

Drop one tag

Drop the drop-by:Partition000 tag from any extent in table that is tagged with it:

.drop extent tags from table MyOtherTable ('drop-by:Partition000')

Drop several tags

Drop the the tags drop-by:20160810104500, a random tag, and drop-by:20160810 from any extent in table that is tagged with either of them:

.drop extent tags from table [My Table] ('drop-by:20160810104500','a random tag','drop-by:20160810')

Drop all drop-by tags

Drop all drop-by tags from extents in table MyTable:

.drop extent tags <| 
  .show table MyTable extents 
  | where isnotempty(Tags)
  | extend Tags = split(Tags, '\r\n') 
  | mv-expand Tags to typeof(string)
  | where Tags startswith 'drop-by'

Drop all tags matching specific regex

Drop all tags matching regex drop-by:StreamCreationTime_20160915(\d{6}) from extents in table MyTable:

.drop extent tags <| 
  .show table MyTable extents 
  | where isnotempty(Tags)
  | extend Tags = split(Tags, '\r\n')
  | mv-expand Tags to typeof(string)
  | where Tags matches regex @"drop-by:StreamCreationTime_20160915(\d{6})"

Sample output

OriginalExtentId	ResultExtentId	ResultExtentTags	Details
e133f050-a1e2-4dad-8552-1f5cf47cab69	0d96ab2d-9dd2-4d2c-a45e-b24c65aa6687	Partition001
cdbeb35b-87ea-499f-b545-defbae091b57	a90a303c-8a14-4207-8f35-d8ea94ca45be
4fcb4598-9a31-4614-903c-0c67c286da8c	97aafea1-59ff-4312-b06b-08f42187872f	Partition001 Partition002
2dfdef64-62a3-4950-a130-96b5b1083b5a	0fb7f3da-5e28-4f09-a000-e62eb41592df